Chris's Diesbar Engine Build

[crueby]

Busy morning on the mill today. Started by finding a thin (0.030") piece of 1" wide steel in the racks, which I will use for covering the slot in the rings that I'm about to cut. The steam/exhaust passages will come from the trunnions up to the steam chest. On the original they would have been cast in place, for the model I'll mill a slot around the ring block and cover it over with this thin material. First step was to roll the steel to the diameter needed, using a small ring roller. Each piece is long enough for one cylinder, they will be cut down into two shorter pieces when fitting them to the ring blocks, and screwed or riveted in place.

Then set up the ring blocks on the vertical rotary table, and milled the shallow recesses for the cover plates:



Then laid out and milled in the slots that will form the passages themselves.

and plunge milled slots at the ends of each one to connect with the holes in the ends of the trunnions

The flats for the steam chest were then milled in. The rings will be too thin to put the flats down to be the full width of the steam chests in one go, so I stepped down the flats - will make the steam chests with matching steps, and bed them in with some JB Weld and hold them in place with some screws.

The ring blocks so far. One step not shown - I milled across the ends of the trunnions on the inside of the rings, to speed up the final boring to size of the rings. In the previous picture you can see a line drawn around the perimeter of the block - that is about where the rings will be bored out to, showing how little material would have been left if I had milled the flats all the way across at full width of the steam chests.

Next time I'll start fitting the cover plates over the passages... 

[Michael S.]

Well done!
That's how it will work.   

[crueby]

Well done!
That's how it will work.   

[Michael S.]

Here are a few more pictures of these oscillating cylinders—but from a different ship.

Michael

[crueby]

Excellent  pictures! Interesting  to see how they cast in the mount for the counterbalance weight  and also the passages.   


Just looked up the Meissen, also a Penn engine, but it was converted to be a compound engine in 1914.


Do you know how many of the ships in their fleet have the Penn engines?

[Kim]

You have a very carefully orchestrated sequence of operations here, Chis. It's looking very fine! 

Kim

[crueby]

You have a very carefully orchestrated sequence of operations here, Chis. It's looking very fine! 

Kim

Thanks  Kim!  Been planning this one for a while. This sequence is plan 7.4...

[crueby]

This morning's shop playtime got the inside of the ring blocks bored out to final size,

and the cover plates for the steam/exhaust passages fitted. The rolled pieces for the covers were cut in half, then one end of each piece was taken to the belt sander and the corners rounded to fit the inside corners of the recesses. With them clamped in place, holes were drilled and countersunk to take some small countersunk flathead screws:

After all four were drilled/tapped and the screws run in, the overhang at the steam chest end was trimmed off with an end mill, taking a couple shallow passes at the level of the flats:

That way the edges of the steam chest base will cover the ends of the panels, and give a place for some epoxy to bed in the base and seal the end of the panel. The panels will also be bedded in some epoxy, then the screw heads will be filed/sanded off flush, leaving part of the head in the countersunk recerss. I used a countersink that matched the angle of the screw heads.
And then re-chucked the ring one more time to drill/tap for the counterweights that hang off the back of the cylinder, with a flat around the hole.

And here are the rings so far, sitting on top of the blanks for the cylinders they will slide onto...

Next will maybe start on the steam chest base blocks, or maybe set up the cylinders on faceplates for turning... Hmmm... decisions decisions...   

[cnr6400]

  The ring assemblies are coming along fast! The passage cover plates look great.

Have the shop elves made 127 trips yet with the Mann truck to get all the solid gold  brass swarf out to the bin?

[crueby]

The ring assemblies are coming along fast! The passage cover plates look great.

Have the shop elves made 127 trips yet with the Mann truck to get all the solid gold  brass swarf out to the bin?

Running the truck half the night, cackling about how many millikegs of beer they can buy...

[Michael S.]

Hi Chris,

The two paddle steamers "Dresden" and "Leipzig" feature inclined steam engines with Lenz valve gear. All the other paddle steamers—seven in total—are equipped with oscillating steam engines; of these, only the steamer "Diesbar" was built by Penn.

The others utilize Stephenson valve gear.

Michael

Steamer: Meissen
   
<a href="https://www.youtube.com/watch?v=YC2sJhzFIKI" target="_blank">http://www.youtube.com/watch?v=YC2sJhzFIKI</a>

[crueby]

Hi Chris,

The two paddle steamers "Dresden" and "Leipzig" feature inclined steam engines with Lenz valve gear. All the other paddle steamers—seven in total—are equipped with oscillating steam engines; of these, only the steamer "Diesbar" was built by Penn.

The others utilize Stephenson valve gear.

Michael

Steamer: Meissen
   
<a href="https://www.youtube.com/watch?v=YC2sJhzFIKI" target="_blank">http://www.youtube.com/watch?v=YC2sJhzFIKI</a>

Thats quite a fleet!  Thanks for the video of the Meissen, that is a very compact engine. The Stephonson linkage barely fits in there!


 

[crueby]

Next will maybe start on the steam chest base blocks, or maybe set up the cylinders on faceplates for turning... Hmmm... decisions decisions...   

Realized that I need to have the ring on the cylinder and machine in some flats on the cylinder to fully shape the steam chest bases, so that makes the decision easy - set up the cylinders for turning next!   

I'll need to set up some plexi spacers on faceplates, and drill the faceplates and the cylinder blanks to bolt them together. That way I can bore through the cylinder blank without hitting the faceplate. I'll bolt them up so that the top flange is against the faceplate, so I can turn the outside down on the rest of the cylinder to fit into the ring. Also need to drill the end caps at the same time to ensure everything matches. And I want to check the tram on the mill before doing any of that. Lots to do... 

[crueby]

This morning got a bunch of holes drilled and tapped. Started with the two faceplates (so I can leave each cylinder on its faceplate through all the turning/boring operations). Then drilled the plexiglass discs that I'll use between the cylinders and the faceplates so I can bore all the way through, and the top cover blanks, all these holes were 4-40 clear.

and then the cylinder blanks - these holes were tapped 4-40

Got the holes in the cylinders all tapped, here first cylinder is assembled with the plexi plate and the faceplate, second one ready to go

and first one on the lathe with tailstock live center support, ready to turn the outside down to fit the ring made already. The faceplate end will be left full size, to form the top cover flange. Also will leave a slight step where the ring will sit, that will make installing the ring simpler - slide it on up to the step. And what looks like rust on the faceplate in this picture is just the paper covering on the plexiglass!

After the outsides are turned, I'll set up the steady rest, remove the tailstock support, and get ready to bore out the cylinders. The shop elves are standing by with their wheelbarrows and trucks to steal all the chips...

[cnr6400]

  Cylinder blanks and drilling look great Chris.

I'm glad you mentioned the release paper on the plexiglass disk - it wasn't clear....     sorry worst pun this week...

Don't be surprised if the shop elves start building a conveyor belt for the millions of cubic micrometres of swarf and chips from the cylinders. Brass swarf outbound on it is OK but Elfensteiner stubbies inbound could be an issue!